As recording media for recording various types of software such as video data, audio data, or data for computers, recording media such as magnetic disks, optical discs and magneto-optical discs have been popularized. For these recording media, various formats are prescribed by predetermined standards.
In recent years, the advancement of the high-efficiency coding technique has enabled band compression of all kinds of data including video data so that these data are handled as digital data. Along with this, increase in capacity of recording media and improvement in recording density are demanded. As techniques for realizing a higher density of recording data, narrowing of the track pitch, change of the linear velocity, change of the modulation system and the like may be considered.
However, in the case of increasing the recording capacity by changing the recording density of an existing recording medium, the address management method on the disc differs depending on the recording format.
For example, with an existing magneto-optical disc, in the case of recording data at a high density using a different recording format, the quantity of recording data increases and therefore a problem arises that clusters/sectors represented by ADIP (address in pre-groove) addresses recorded in advance on grooves of the magneto-optical disc do not coincide with data blocks, which are actually handled as recording/reproducing units.
Random access is carried out with reference to ADIP address. When reading out data in random access, it is possible to read out desired recorded data by accessing a part near the position where the desired data is recorded. However, when writing data, it is necessary to access an accurate position in order not to overwrite and erase already recorded data. Therefore, it is important to accurately grasp the access position from the cluster/sector of each data block unit associated with ADIP address.